textproduct: Quad Cities

KEY MESSAGES

- Light rain will be seen in areas west of the Mississippi River through Saturday night, with mostly dry conditions moving in Sunday through Monday.

- Another active weather pattern will set up in the middle of the upcoming work week, bringing the potential for rounds of heavy rainfall and thunderstorms to the area.

- Temperatures will remain near to slightly above seasonal norms through the next week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 124 AM CDT Sat Sep 26 2026

Upper ridge remains situated over the Mississippi River Valley through today, with it starting to break down Sunday through Monday. A ridge-riding wave will dig into our area from the west today, which will start to break down this ridge. Best moisture transport will be off to our west, with drier east to southeasterly flow kicking into our east, leaving the Mississippi River as the rough delineation line for rain chances. Best chances for rainfall (50-80% PoPs) will be west of the Mississippi River in parts of eastern Iowa this morning into early afternoon. We are not expecting widespread heavy rainfall. Rather, we should see spotty light showers passing through, with dry time between. Dry air east of the river should keep much of the rainfall chances <20%. With that said, there will still be some battle with dry air west of the river. Thus, rainfall should remain light. Later this afternoon and into the evening, rainfall chances will decrease, prior to increasing once again overnight tonight into Sunday AM (20-40% PoPs). Similar locations will be in line for more light rainfall. When all is said and done, rainfall accumulations through Sunday AM will be low, generally <0.10-0.20" for eastern Iowa and locations east of the Mississippi River that manage to see light rain will see <0.10". Compared to the previous forecast package, the trend has been decreasing and a little more west with the rainfall. Overall, we are still looking at another dreary day for some through Saturday, with cool temperatures in the 60s and a light southeasterly breeze. Areas east of the Mississippi River will have the best chance to see temperatures warm near 70 with more potential breaks in the clouds, especially through early afternoon.

Upper ridge will continue to slowly break down through Sunday, with surface high pressure strengthening over the Great Lakes Region. We will start to see this build westward a bit, which will help usher drier air into the area. Thus, precipitation chances will largely deplete through the day Sunday into the new work week. Although, we will continue to see mostly cloudy skies through the remainder of the day. Temperatures will remain in the 60s with light easterly winds through the afternoon. Overnight temperatures will be in the 50s throughout.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 124 AM CDT Sat Sep 26 2026

Going into Monday, we will continue to see influence from the building high pressure over the Great Lakes Region. A greater push of dry air will work into the area, allowing for the potential for more breaks in the clouds. This will be a welcome sight for those that have been socked in clouds and light precipitation this weekend. Overall, we are expecting to remain dry through Monday, with temperatures warming to near 70 throughout.

This period of dryness will come to an end mid-week as a larger system builds in sometime around Tuesday/Wednesday. A longer wave trough, with models showing a strong tropical connection to the systems from the eastern Pacific and the Gulf, should translate through the area, although the exact onset/ending time of associated precipitation remains uncertain. This is pretty clearly shown from the LREF ensemble cluster analysis, which shows various depictions of the longer wave trough aloft. Some show a large progressive trough sweeping across the central CONUS, while some show a slower cut-off low with multiple rounds of rain mid to late week. However, there remains a strong signal for abundant moisture with this system given the tropical connection, with Pwat values progged around 1.6 to 2 inches, which is quite high for late September. In fact, these values would be in excess of the 99th percentile for Pwats per the NAEFS climatological percentiles. NBM exceedance probabilities for one inch or more of rain for Tuesday night and Wednesday are around 40-60%, which is actually a pretty decent signal given we're talking several days out. Despite the uncertainty on the exact duration and magnitude of rainfall amounts, this signal appears supportive of heavy rainfall and perhaps a flash flooding threat, given wet antecedent conditions. So, this mid-week system bears watching. With this, WPC has much of our area in a Day 5 Slight Risk (level 2 of 4) in their latest excessive rainfall outlooks.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 551 AM CDT Sat Sep 26 2026

VFR conditions will continue through the period, though the morning hours will feature a band of high based rain showers moving east/northeast from central Iowa and Missouri. These showers will be encountering much drier air as they move into eastern Iowa, which should cause them to diminish this morning as they arrive. A few spotty light showers remain possible into this evening, but with coverage low and expectations of VFR weather, we will not include in the TAF on this issuance.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.